Electro-optical method and apparatus



J. c. BATCH ELOR 2,307,661

Jan. 5, 1943.

ELECTRO-OPTICAL METHOD AND APPARATUS Filed Feb. 20, 1941 8 FIGURE 0UTPUT I I I? i 1 FIGURE 2 OUTPUT Patented Jan. 5, 1943 ELECTED-OPTICAL METHOD AND srrans'rus John C. Batchelor, Hastings on Hudson, N. Y. Application February 20, 1941, Serial No. 379,763

3 Claims.

My invention relates to the art of composite television image production of the type wherein a plurality of objects are scanned in a manner such as to produce combined television signals capable of effecting the reproduction of an image illusive of having been produced by the scanning of a single scene. 7

Various methods and apparatus have been proposed in the past for accomplishing this result, but I know of only two such proposals which are not subject to the operating aberration of ghosting," or the intermixing of signals from the two scanned scenes at points where they should be mutually exclusive. The two proposals which obviate this shortcoming are those disclosed in United States Patents 2,073,370 and 2,113,473. These, however, require sufllcient equipment and precision of operating adjustment to leave room for further improvement in the art of composite television image reproduction.

Accordingly, it is a principal object of my invention to provide improved methods of and apparatus for scanning a plurality of images to produce television signals corresponding thereto and modifying the produced signals to produce a single set of signals capable, when an image is reproduced therefrom, of creating the illusion that a single field of view was scanned.

This and other objects will appear in the description of my invention which follows.

In accordance with one form of my invention, I prefer to use a plurality of television scanning devices, one of which is caused to scan objects which are destined to appear as foreground objects in the reproduced image, andat least one other of which is caused to scan a negative image of objects destined to become background objects in the reproduced image, to which image will have been added a sufficient portion of the foreground image to cause the signals generated by the second scanner to correspond to whiterthan-white in the negative image projected thereon, which will .in turn correspond to a blacker-than-black level in an image reproduced therefrom with positive polarity. I then mix the signals of both scanners with appropriate polarity to produce television signals such as might have been produced by the scanning of a single object v group with a single scanner.

appropriate for mixing with the foreground signals to yield composite signals as before.

There are other particular aspects of my invention, but to bring these out more clearly, attention is directed to the accompanying drawing in which.

Figure 1 is a schematic diagram of one form which my invention may take; and

Figure 2 is a schematic drawing of another form of my invention which presents certain operating advantages. 7

Referring now to Figure 1, I have provided an object 3, representing the foreground view to be analyzed, performing before a relatively nonreflective background 4. An image scanner 6, of any desired type such as that known as an lconoscope, and having an image receiving screen 5 is associated with the objective lens I so constructed and disposed as to image the object 3 on the screen 5. A forty-five degree transparent mirror 8 is provided in the optical path between the object 3 and the scanner 6 so that a portion of the light from the object 3 is deflected and imaged on the image screen 9 of the second scanner l0.

At the same time, a second image is projected upon the screen 9 through the mirror 8 by the lens II, and thisimage may be in the form of a negative image of the background before which it is desired that the object 3 appear to be in action. Thus, avnegative transparent slide l2 of the desired background may be the object for the lens H, being illuminated by the system compris ing the lamp l3 and the condenser l5. It will be understood that a negative image is one in which the lights and shades are in approximately inverse order to those of the original subject. Inasmuch as a portion of the image from the object l2 will be reflected by the mirror 8 onto the screen 5 of the scanner 6, I prefer to make the screen 5 insensitive to some particular color of light, for example, blue, and to provide a filter M in the path of light from the lamp l3 so that the scanner 6 will produce no signal corresponding to the background slide l2.

The image of the object 3 which is projected onto the screen 9 is projected with such intensity that any part of the screen 9 which receives any li ht whatever from the object 3 will receive sufficient light therefrom to cause those areas of the screen 9 to be charged to saturation, or at least to extents which will produce whiter-than-white signals, so that those areas will be insensitive to other additions of light. Accordingly, portions of the background image which fall on the screen 9 at points where light from the object 3 impinges will produce no effect thereon.

Thus, it will be seen that the scanner 6 will produce positive signals corresponding to the foreground object performing before a dark background, and these signals may be amplified by the amplifier ll having 11 stages. Similarly, the scanner ID will produce signals corresponding to the negative background slide l2 on which a white silhouette of the foreground object I is superimposed, and when this signal is amplified by the amplifier l6 having n- (2k1) stages, a positive background signal will result corresponding to the background on which is superimposed a black silhouette of the object 3.

If now the output signals from the amplifiers l6 and II are mixed, a resultant composite signal will be produced which, when reproducedx will yield images which appear as though the object 3 had been performing before a background delineated by the slide 12.

It will be seen that in the embodiment of Fi ure 1, a certain amount of light from the object 3 will be absorbed or diverted by the mirror 8 before it reaches the screen of the scanner 6, and in view of the fact that the greatest'possible sensitivity and the minimum possible scene illuminating intensity are desirable, I sometimes modify the embodiment of Figure 1 as shown in Figure 2, to improve the optical efficiency of the system and for other reasons.

In Figure 2, I have provided the foreground image 3 performing before the substantially nonreflecting background 4 adapted to be imaged by the lens I upon the screen 5 of the scanner 6 to produce image signals which are in turn amplified by the amplifier H. A second scanner Ill having the image screen 9 is provided for reproducing the background signal as before, and its output terminal is connected to the amplifier l6.

The screen 9- receives an image of the background slide i2 as before, projected thereon by the lens H through the forty-five degree transparent mirror 8. A second image portion is projected upon the screen 9 by the system including the mirror 8, the lens 22, the image reproducin screen 2| of the image reproducer and the amplifier I9 energized by signals corresponding to the foreground object 3 from the amplifier IT. The amplifier I9 is adapted to yield signals which will cause the image reproducer 20 to produce an image whose light intensity is either maximum value or is completely black with no intervening shades, or alternately, of sufilcient intensity that the presence of any light whatever from the screen 2| upon the screen 9 will produce signals corresponding to a whiter-than-white level. Thus, the scanner ID will produce signals which, when properly polarized, correspond to a positive of the background object I! against which appears a black silhouette of the object 3 and when the outputs of the amplifiers l6 and I! are mixed as before, a composite image will be pro-. duced which, when reproduced, appears to have been generated by scanning the object 3 performing directly before the background l2. It will be understood, of course, that signals from the amplifier l6 will preferably be prevented from entering the input terminal of the amplifier l9, as by buffer stages or the like, At times, however, certain amounts of feedback may be found desirable.

It will now be clear to those skilled in the art that it matters little which of the slide l2 and the image on the screen 2| be negative, it bein necessary only that they be of opposite sense in this respect. In this embodiment, it will be seen that I have eliminated the transparent mirror from the optical system of the foreground scanner, and, hence, substantially smaller intensities of illumination on the object will suflice to produce adequate signals from the scanner 6.

It will be understood that many further modifications of my invention will occur immediately to those skilled in the art, and the following claims, rather than the foregoing specification, will be understood to define the scope of my invention.

I claim:

1. A televisoin image analyzing system adapted to produce a series of composite signals representing a composite scene including portions of at least two scenes comprising a first scanning device for producing signals corresponding to a foreground scene, a second scanning device including a signal amplifier for producing signals corresponding to a background scene and being responsive to light intensities up to a predetermined value whereafter response is substantially reduced, means for projecting a foreground image on said first scanning device, means for projecting a negative image of a background scene upon said second scanning device, means for projecting a second foreground image on said second scanning device similar to said first foreground image and having intensities greater than said predetermined value so that said second scanning device is rendered relatively unresponsive to portions of said negative background image, and means for adding together the signals produced by said firstand second scanning devices to produce a composite signal corresponding to said foreground and background scenes.

2. A television image analyzing system adapted to produce a series of signals representing a composite scene including portions of at least a foreground and a background scene comprising a first scanning device for producing signals corresponding to a foreground scene, a second scanning device for producing signals corresponding those in the image reproduced by said image reproducer, means for projecting said reproduced image upon said second scanning device, and means for adding together the signals produced by said first and second scanning devices to produce a composite signal corresponding to said foreground and background scenes.

3. In the art of television image analysis, the method of producing a series of composite signals representing portions of at least two scenes by the use of at least two electronic scanning devices, at least one of which has an inherent limitation upon the range of light intensity to which it is responsive and beyond which limitation substantially no response occurs, which comprises scanning a first scene to produce a first series of signals, optically adding images of said first scene and of a second scene to producea composite image characterized by the fact that the luminous intensities of portions of said image exceed the maximum intensity to which said response-limited scanning device is responsive and submitting said composite image toanalysis by said scanning device having said inherent limitation to produce a second series of signals, and electrically mixing said first and second produced signals to produce a series of composite signals.

JOHN C. BATCHELOR. 

